Tumor-derived factors such as colony-stimulating factor 1 (CSF1; also known as M-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), CC-chemokine ligand 2 (CCL2), CCL7 (or MCP-3), GDNF, IL-33, CXCL12 (SDF-1) and EGF are responsible for myeloid cell recruitment and promote tumor growth [78,79,80,81]. The gene discussed is GDNF; the disease is neoplasm.